The continuing evolution of all aspects of undersea technologies has produced an astounding variety of innovations which help to solve the many formidable problems posed by this inhospitable frontier. One area where solutions are needed involves the numerous data gathering sensors required for meaningful analysis and proper action. They must have reliable data transmission links that span the distance between the sensors and central processing facilities.
While some noteworthy advances have been made in the optoelectronic field, the more or less conventional electronic sensors and their associated electrical cables have left something to be desired. The limitations of the conventional designs have been made particularly acute in applications where the data link is to communicate the sensor's informations from great depths to the surface. Although ideally such an electrical link should transmit the desired information with little or no attenuation, be light in weight and neutrally buoyant as well as very strong, flexible and inexpensive, the weight of suspended electrical cables can be immense. The current cable systems based on copper conductors meet many of these criteria and for this reason copper conductors are usually the material of choice with current technology. However, copper is less than an ideal material when it's weight is considered (specific gravity is about 8.7). Furthermore, the general deterioration of copper in an ocean environment when elaborate safeguards aren't provided and the increasing cost of copper for some expendible systems, make the selection of copper conductors a doubtful choice in some deep ocean applications.
In recent years a nearly neutrally buoyant undersea cable has been developed and widely used. It has a number of copper conductors alone or in combination with a conventional coaxial design and can extend for several hundred feet through the ocean. Floats are attached at predetermined intervals along the length of the cable to make it neutrally buoyant and care must be taken when the cable is being deployed or retrieved to guard against damaging the floats. Obviously this arrangement is bulky and requires special handling considerations. The bulk and mass of this arrangement also poses problems where ocean currents are expected as well as the problems associated with deployment and retrievement through the air ocean interface during high sea states.
Thus, there is a continuing need in the state of the art for an essentially neutrally buoyant undersea electronic data communication link that has a sufficient strength to assure completion of the job as well as possessing suitable bandwidth and frequency response characteristics while being of compact size.